School of Mathematicshttp://hdl.handle.net/2262/1
School of Mathematics

2015-03-03T22:41:24ZA Novel quark-field creation operator construction for hadronic physics in lattice QCDhttp://hdl.handle.net/2262/72894
A Novel quark-field creation operator construction for hadronic physics in lattice QCD
PEARDON, MICHAEL JAMES
A new quark-field smearing algorithm is defined which enables efficient calculations of a broad range
of hadron correlation functions. The technique applies a low-rank operator to define smooth fields that are
to be used in hadron creation operators. The resulting space of smooth fields is small enough that all
elements of the reduced quark propagator can be computed exactly at reasonable computational cost.
Correlations between arbitrary sources, including multihadron operators can be computed
a posteriori
without requiring new lattice Dirac operator inversions. The method is tested on realistic lattice sizes with
light dynamical quarks.
PUBLISHED
2009-01-01T00:00:00ZPolynomial Filtered HMC: An Algorithm for lattice QCD with dynamical quarkshttp://hdl.handle.net/2262/72893
Polynomial Filtered HMC: An Algorithm for lattice QCD with dynamical quarks
PEARDON, MICHAEL JAMES
Polynomial approximations to the inverse of the fermion matrix are u
sed to filter the dynamics of the upper energy
scales in HMC simulations. The use of a multiple time-scale integration sc
heme allows the filtered pseudofermions to be
evolved using a coarse step size. We introduce a novel generalisatio
n of the nested leapfrog which allows for far greater
flexibility in the choice of time scales. We observe a reduction in the com
putational expense of the molecular dynamics
integration of between 3–5 which improves as the quark mass decre
ases.
PUBLISHED
2012-01-01T00:00:00ZExcited D and Ds meson spectroscopy from lattice QCDhttp://hdl.handle.net/2262/72892
Excited D and Ds meson spectroscopy from lattice QCD
PEARDON, MICHAEL JAMES; RYAN, SINEAD MARIE
2012-01-01T00:00:00ZHighly excited and exotic meson spectrum from dynamical lattice QCDhttp://hdl.handle.net/2262/72891
Highly excited and exotic meson spectrum from dynamical lattice QCD
PEARDON, MICHAEL JAMES
Using a new quark-field construction algorithm and a large variational basis of operators, we extract a highly excited isovector meson spectrum on dynamical anisotropic lattices. We show how carefully constructed operators can be used to reliably identify the continuum spin of extracted states, overcoming the reduced cubic symmetry of the lattice. Using this method we extract, with confidence, excited states, states with exotic quantum numbers (0+-, 1-+, and 2+-), and states of high spin, including, for the first time in lattice QCD, spin-four states.
PUBLISHED
2009-01-01T00:00:00Z